On (10/07/07 13:04), Peter Zijlstra didst pronounce:> On Tue, 2007-07-10 at 11:20 +0100, Mel Gorman wrote:> > <snip>> > > > lumpy-reclaim-v4.patch> > > > This patch is really what lumpy reclaim is. I believe Peter has looked> > at this and was happy enough at the time although he is cc'd here again> > in case this has changed. This is mainly useful with either grouping> > pages by mobility or the ZONE_MOVABLE stuff. However, at the time the> > patch was proposed, there was a feeling that it might help jumbo frame> > allocation on e1000's and maybe if fsblock optimistically uses> > contiguous pages it would have an application. I would like to see it go> > through to see does it help e1000 at least.> > I'm not seeing how this will help e1000 (and other jumbo drivers). They> typically allocate using GFP_ATOMIC, so in order to satisfy those you'd> need to either have a higher order watermark or do atomic defrag of the> free space.>

It does help somewhat indirectly and in an unsatisfactory manner. When thehigher watermarks are breached, the atomic allocation will still succeeedbut kswapd will be poked to reclaim at a given order. This is similar tothe problems SLUB hits when it uses high-orders frequently.